Add gmock into our dependencies.

third_party/boost/boost/config/platform/beos.hpp

Index: third_party/boost/boost/config/platform/beos.hpp
diff --git a/third_party/boost/boost/config/platform/beos.hpp b/third_party/boost/boost/config/platform/beos.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..48c3d8dc5bad52d049318c494ee91e6536152a42
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+++ b/third_party/boost/boost/config/platform/beos.hpp
@@ -0,0 +1,26 @@
+//  (C) Copyright John Maddock 2001. 
+//  Use, modification and distribution are subject to the 
+//  Boost Software License, Version 1.0. (See accompanying file 
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+//  See http://www.boost.org for most recent version.
+
+//  BeOS specific config options:
+
+#define BOOST_PLATFORM "BeOS"
+
+#define BOOST_NO_CWCHAR
+#define BOOST_NO_CWCTYPE
+#define BOOST_HAS_UNISTD_H
+
+#define BOOST_HAS_BETHREADS
+
+#ifndef BOOST_DISABLE_THREADS
+#  define BOOST_HAS_THREADS
+#endif
+
+// boilerplate code:
+#include <boost/config/posix_features.hpp>
+ 
+
+